Alright...let's try this. I know you've done most of these tings before but
let's take them in order.
Disable System restore.
Download updated virus definitions for your AV program.
Download HijackThis (do a Google search) and see if anything suspicious is
listed. Be careful.
If you use Spybot, Spyare Guard, Adaware, or others, download latest
definitions.
If the hack is in MSCONFIG, note the path to the file then disable it in
MSCONFIG.
Follow the noted path and delete the file if found.
Uninstall the game.
Uninstall the hack (if present)
If the hack is in the registry,
(SOFTWARE/Microsoft/Windows/Currentversion/Run) delete it.
While in the registry, do a search for the file and if found, delete all
references to it.
Open Task Manager and see if the hack is running in the process list.
Navigate to the C:\Program files directory and delete the folder for the
game (if present).
Navigate to the C:\Program files and delete the folder for the hack (if
present).
Navigate to the C:\Windows\Prefetch and delete the contents (not the folder
itself).
Run a free online virus scan from somebody like
www.pandasoftware.com./acvtivescan.
Make notes of any suspicious things it finds but doesn't delete.
Find those things from Panda and manually delete them.
Restart in safe mode.
Run your antivirus. If stuff is found, clean it and run again until nothing
is found.
Run Adaware and etc. If stuff is found, clean it and run again until
nothing is found.
If the hack is still in MSCONFIG, note the path to the file then disable it
in MSCONFIG.
Follow the noted path and delete the file if found.
If the hack is in the registry,
(SOFTWARE/Microsoft/Windows/Currentversion/Run) delete it.
While in the registry, do a search for the file and if found, delete all
references to it.
Open Task Manager and see if the hack is running in the process list.
Navigate to the C:\Program files directory and delete the folder for the
game (if present).
Navigate to the C:\Program files and delete the folder for the hack (if
present).
Look for those things from Panda that weren't cleaned and manually delete
them (if present).
Restart computer. Your computer has something listed somewhere that is
calling this program to run when it starts. It may be in the registry,
startup items or just hidden someplace sneaky. Also, I'm not clear on
whether you are still getting the message on boot up or when you start the
game. Let us know how the above works for you.